Only getting heat at IDLE!?

Austen Bickley

New Member
After a bit of advice...

For some reason my car has now started only giving heat whilst at idle? At any sort of speed its just cold air that blows out.

Ive seen countless threads of it being the other way around but none like this?

Why would it only give heat at idle but not at speed? Surely if the heater core was blocked id get no heat at all? Or at speed/high revs?

Thanks for the help
 

Harvey

VAG Convert
Might be flap issue possibly actuator if it's climate with the heater assembly & your getting heat soak from the matrix (not the movie) when not moving. Then when the cars moving the cold air is coming in & blowing more than the hot air.

Get your codes read & do an actuator test and/or basic setting for the heater, I believe it's module 08 if you know anyone with VCDS. A basic setting will move all heater related actuators full travel both ways & flag any faults if the actuators are dodgy. That's where I'd start before taking things apart.
 

Austen Bickley

New Member
Funnily enough Ive just got to pick up my new vcds from gendan from the post office today, however I have no idea how to use it so that will be a learning curve

I located what I think to be the coolant pipes going through the fire wall, one seems to be roasting and the other quite cool, this suggests a blocked core? Or is there some form of control valve?
 

Harvey

VAG Convert
Regards your firewall heater matrix pipes, sounds like a blockage to me. I've read the silica bag in the heater tank can split so might be worth checking that but sounds like a blockage in the matrix to me.
 

MarttiMat

Registered User
Funnily enough Ive just got to pick up my new vcds from gendan from the post office today, however I have no idea how to use it so that will be a learning curve

I located what I think to be the coolant pipes going through the fire wall, one seems to be roasting and the other quite cool, this suggests a blocked core? Or is there some form of control valve?

While your issue is different from the OP in this thread, there is some good info in relation to our HVAC system here:
https://www.audi-sport.net/xf/threa...from-passenger-side-vents-with-a-c-on.419746/

Take a read and see if there are any faults in the climate control head as a starting point.
 
Its prob your thermostat/water pump that needs to be changed. Its most likely sick open and when you are moving, the coolant is cooled and why you are not feeling the warmer heater air.

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